No. LG Q6 Plus does have the LED notification light and it also has the Always-On display.
LG Q6 Plus SAR value is as follows:
SAR Value (Head): 0.72 Wkg@1g
SAR Value (Body): 0.455 Wkg@1g
No. LG Q6 Plus comes with 1.2 A power charger which is not fast charger. But you can use Sony CP-AD2 USB charger to charge LG Q6 Plus faster.
Yes, LG Q6 Plus does support Miracast.